WebDAV is a technology that makes the Web a collaborative, writeable medium. WebDAV stands for “Web Distributed Authoring and Versioning.” Today the Web is really read-only, where people mostly do downloading and reading operations. WebDAV makes it possible for web users wherever they are, whether separated by two houses or two continents, to write, edit and save shared documents without scuttling each other's work, regardless of which software program or Internet service they are using. Today, when people want to collaborate on a document, they usually pass it back and forth using email. This is a messy, error-prone process. Confusing email encoding problems can prevent successful sending of a document. Over time, sending files back and forth leads to problems keeping track of all the old versions of the file. Plus, in some companies, emailing a big file can take a long time when the network is busy. With WebDAV, the encoding problem goes away, and information is immediately available after it is saved. Instead of emailing the entire file, with WebDAV you just email the URL. WebDAV is also better than FTP because it is significantly faster, is in the same namespace as the actual published documents, and is consistent with other “web” tools. In addition, WebDAV has overwrite prevention and property management operations, both absent from FTP.
However, WebDAV goes beyond just Web page authoring. WebDAV is a set of extensions to the Hypertext Transfer Protocol (HTTP), which is the standard protocol that allows Web browsers to talk to Web servers. WebDAV and HTTP can accommodate all kinds of content, and so WebDAV can be used just as easily to collaboratively work on a word processing document, a spreadsheet, or an image file. Anything you can store in a file can potentially be authored using WebDAV, gaining its advantages.
WebDAV has three main features: overwrite prevention, properties, and namespace management. Overwrite prevention is important because it allows people to avoid the “lost update problem” that occurs as changes to a document are lost when several authors access and attempt to edit a file at the same time. By ensuring that people can work together without losing their changes, overwrite prevention is the key to WebDAV's collaboration support.
WebDAV's properties feature is an efficient means of storing and retrieving what is known as “metadata”—information about a web document such as the author's name, copyright, publication date and keywords that Internet search engines use to find and retrieve relevant documents. Finally, WebDAV also has what is called “namespace management” capabilities, which enables users to conveniently manage Internet files and directories, including the ability to move and copy files. The process is similar to the way word-processing files and directories are managed on a regular computer.
Another advantage of WebDAV is the ease with which individual Web pages can be made. On many sites, the process for getting Web pages up and running is very complicated. WebDAV-enabled applications can allow a person to just save to a URL, thus avoiding the hassles of shell accounts, FTP, and the details of how file system directories are mapped into URLs.
Additionally, many sites have a staged production process. This involves a content submission area, one or more staging areas, and a publicly visible area. Sites like this will not use WebDAV for the publicly visible area, since they want to maintain the integrity of the site. However, WebDAV offers a great deal for the content submission and staging areas. Big web sites often collect information from people across an organization, and sometimes from several different organizations. Very frequently, the contributors are geographically dispersed. WebDAV provides a standard way for contributors to submit their information. As a web site developer, one can create a submission area, hand out its URL, and let people save directly to it.
While WebDAV is very useful insofar as its ability to enable distributed authoring and versioning, integrating its functionality with existing Internet servers poses challenges that must be overcome if the two systems are to coexist peacefully. One such challenge relates to the processing of HTTP requests that operate on more than one file resource. In an HTTP environment, a virtual namespace is exposed to clients. The virtual namespace defines resources in terms of a tree-like directory and sub-directory hierarchy. However, this directory hierarchy does not necessarily correspond to the actual physical storage media upon which the resources reside. Rather, virtual directories and sub-directories, often referred to as “virtual roots,” are mapped to different physical storage locations that might not correspond to the virtual directory hierarchy.
HTTP requests of the past (GET and HEAD requests in particular) did not pose a problem in this environment because these requests simply operated upon one and only one specified resource. With the advent of WebDAV, however, it is more likely than not that requests will involve or specify operations on a plurality of different resources, potentially involving disparate physical locations.
Along with this traversal operation arise concerns associated with integrating the conventional web server functionality with the newer WebDAV functionality so that operation is transparent to the client.
This invention arose out of concerns associated with providing methods and systems for integrating WebDAV with current Internet servers.